1. Field of the Invention
The present invention relates generally to dry-mate connectors which are intended to be mated in a dry environment and then exposed to a harsh working environment, such as seawater.
2. Related Art
Dry-mate connectors typically consist of plug and receptacle units which, when mated together, form a sealed chamber around the contact elements. The plug unit typically contains a plurality of contact probes or pins to which fiber-optic or electrical leads are terminated. The receptacle unit contains a corresponding number of sockets into whose terminal ends a corresponding number of fiber-optic or electrical leads are terminated. The probes or pins are mated with the sockets when the two units are coupled together.
One type of dry-mate connector comprises rubber plug and receptacle portions which depend on a squeezed interference fit between the plug and receptacle portions to accomplish the seal. They are typically referred to as “interference-fit” connectors and have been in common use for many years. Interference fit connectors are typically not suitable for high reliability applications. Interference fit connectors are used to connect electrical circuits only. Their somewhat deformable bodies do not allow the precise contact alignment required for optical circuits.
Another known dry-mate connector consists of rigid plug and receptacle units that are typically, but not always, formed from metal. Such connectors have been used for more than 50 years. They are typified by MIL-C-24217, a military specification describing the construction of one commonly used electrical connector embodiment. To create the sealed contact chamber, these connectors rely on rubber O-rings that sealably engage as the plug and receptacle portions are mated. These connectors are suitable for both electrical and optical circuits, and for high-reliability applications.
Even the MIL-C type electrical connectors have some operational shortcomings. Often the environment in which they are connected/disconnected is a spray or splash zone, or simply very humid. If even a single droplet of water or a bit of dampness enters the contact area prior to complete engagement, the connector fails electrically. These connectors have no internal protection that prevents contact-to-contact or contact-to-shell electrical shorting in such circumstances.
Attempts have been made to provide internal protection on already-manufactured connectors by inserting a secondary gasket seal between the mating faces of the connector halves. Such an arrangement is proposed in U.S. Pat. No. 4,909,751 of Marolda, for example. These rigid body dry-mate connectors, however, are not manufactured with surfaces that can be easily or reliably sealed with such gaskets. In any case, the gaskets themselves are susceptible to dampness. So the secondary gasket seal does not completely address the problem.
There are existing dry mate connectors of the rigid body type that are capable of carrying optical circuits, for example as described in U.S. Pat. No. 5,873,750 of Cairns et al. In such connectors, the optical contacts consist of single-circuit straight-termination type ferrules. Because each optical contact within these connectors requires its individual, respective ferrule, the number of optical circuits in any one connector is limited. All dry-mate connectors of this sort have used individual ferrules to align the optical circuits, leading to increased complexity, large connector size and high cost as optical channel count grows.